Interaction-Driven Dynamics of a Bose-Einstein Condensate in an Optical Lattice
Primary author: Md Kamrul Hoque Ome
Co-author(s): Peter Engels; Sean Mossman; Thomas Bersano
Faculty sponsor: Peter Engels
Primary college/unit: Arts and Sciences
Ultracold clouds of atoms, with temperatures near absolute zero, placed into carefully designed laser fields form an excellent tool for probing the dynamics of interacting, quantum mechanical particles. A laser field shaped in the form of a standing wave provides a periodic array of traps for the atoms, leading to a band structure. In this work, we investigate the existence of peculiar loops in these bands that are predicted to occur for sufficiently strong interactions between the atoms. In our experiments, we apply laser cooling and related techniques to create an ultracold ensemble of atoms called Bose-Einstein condensate. By ramping up laser fields and dynamically changing their frequencies, the band structures can be analyzed. The experiments reveal a non-exponential tunneling of atoms between the individual sites of the trapping potential which is connected to the predicted loop structures. This is a significant finding for this area of research because non-exponential tunneling has not been observed before. In conclusion, this work provides a clear demonstration of the power of ultracold atoms for investigating complex quantum mechanical dynamics.